Culex tarsalis

Culex tarsalis

Culex tarsalis is widely distributed west of the Mississippi River, and therefore found throughout South Dakota. Females feed mainly on birds, but will also attack humans and domesticated animals. They are most active at dusk, and will enter buildings in search of a blood meal. Adult females can hibernate in the northern United States, and larvae are produced from early spring until late fall. Culex tarsalis is larger than Ae. vexans and is pale brown in color. Culex tarsalis is characterized by a broad white band on the proboscis and apical and basal white bands on the tarsi. A small white dot is present on either side of the central area of the dorsal side of the thorax. From each dot, extends a narrow submedian white line to the near posterior margin of the mesonotum. Members of the genus Culex are the primary vectors for the West Nile Virus. A close relative of the Cx. tarsalis, the Cx. pipiens, is the primary carrier of the West Nile Virus along the eastern half of the United States. Culex tarsalis is a very common mosquito in most states west of the Mississippi, and is considered to be the most important vector of viral encephalitis to horses and humans in the western states. West Nile Virus has been isolated from pools of Cx. tarsalis from South Dakota, and this species will very likely be the predominant vector for this virus throughout the western states.